The 3rd Generation Mobile Communication Network (3G) and Next Generation Communication Network (NGN), in which soft switch is used as a control core and Packet Switched Network (PSN) is adopted as a transmission network, are comprehensive and fully open network platforms that may simultaneously provide various services such as voice, data, and multimedia.
In the existing video communication technologies, both parties in a communication may replace a video, but the video to be replaced is downloaded into a user communication terminal by the user himself/herself, and then transmitted to the opposite party. Due to the memory limitation of a communication terminal, the amount of videos that may be replaced and the capability of a service provider to develop new services, such as advertising, are restricted.
The existing 3GPP (The 3rd Generation Partnership Project) Protocol specifies a video phone call process, which is used for realizing video call between 3G users. However, due to problems with 3G network or a user terminal, video call between 3G users cannot be successful all the time. Therefore, 3GPP Protocol also specifies specifications on video call fallback. According to the 3GPP specifications, a calling user is prompted to re-initiate an ordinary voice call when the video phone call fails. Also, in a conventional video call technology, an ordinary voice call is automatically placed again after a video phone call fails. In the prior arts, when a video phone call initiated by a calling user fails, only an ordinary voice call may be re-initiated, and no video may be played to the calling user at the same time when an audio conversation is directly connected between the calling user and the called user, thus the application of new communication operating modes is limited.